This may seem like stupid question but here goes, will it hurt anything to leave my shield 40 loaded with a round in the chamber and cocked with the safety on. I was wondering if it would weaken any springs or linkages or what-not. Thanks for any advice.

Nope. What actually wears out springs is cycling them.

This is just a general response to the topic

If you go over to THR and search "Springs" you will literally get enough information on this topic to fill a book.

They have responses from metallurgists, engineers and manufacturing experts. They discuss design specs, load limits, static compression factors, how magazine capacity affects the springs, yada, yada, yada.

By the time you're finished reading you'll want to tear your eyes out of your head but you you will know all you need to know about springs

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Here you go, one such post by an SME Named Walt Sherril.

[QUOTECarl N. Brown said:
I was told that magazine springs are weakened more by the act of inserting cartridges and removing cartridges than by the status of being left loaded (compressed). Properly tempered springs are weakened by flexing, not by staying uncompressed or compressed.

Added: I take the hint that springs get hot during flexing, stay cold otherwise. Plus magazine springs are designed for a certain range of use, and overflexing them may weaken them quicker than normal use (say, cutting the legs off the follower to allow cramming an extra round or two).[/QUOTE]

Walt's Response
OVERFLEXING is the key. Most 1911 magazine springs will have a long life, and the 7-round mag springs (like those in the WWII mags that were kept loaded) will have the longest life.

According to the experts, including Metallurgists (the engineers who work with and design metals) and others who use springs in aviation, auto, and space applications, flexing/working a spring will have little effect on it's working life unless, as it's compressed, the spring nears or exceeds the springs "elastic limit." (The "elastic limit" is the amount of compression a coil spring experience until it's damaged. Most guns springs (like tappet springs in cars) are designed and used in ways that don't approach that limit. The exception? A lot of very high-cap mags, recoil springs in sub-compact guns, some sub-compact mag springs, etc. In those more-specialized cases, the gun designers consider the springs "renewable resources" and spring life is sacrificed for additional rounds or function performed in a smaller space. When a spring's elastic limit is exceeded, the spring's metal begins to suffer from micro-fractures, and as the spring is used, the amount fracturing continues -- until the spring softens and doesn't function properly. None of this has much to do with the HEAT generated by flexing, but simply has to do with how the steel's structure responds to the amount of flexing/stretching it experiences. Steel is a very resilient material. Aluminum, on the other hand, isn't -- which is why we don't see aluminum used in springs.)

The Rohrbaugh R9 had a recommended recoil spring life of about 250 rounds/cycles. (It had originally been about 100 rounds higher, but they lowered the round count after the gun had been out for a while. The springs weren't that expensive.). The springs might still work after 250 round, but folks didn't want to RISK a failure or poor functionality (like the inability to chamber the next round when used as a carry weapon.)
​The R9 recoil spring was a very small spring stuffed into a very small frame and slide, yet it had to still cycle a 9mm round, stripping a 9mm round from a mag and chambering it. That spring didn't last as long as a full-size spring in a full-size gun firing the same number of rounds.)

With most full-size guns, leaving the mag loaded might not make a difference. For some very high-cap mags, leaving them loaded might shorten mag spring life. If cycling springs alone wore them out, many cars with tappets wouldn't be running -- as those springs cycle many millions of times over a car engine's life. Note: Wolff Springs (in the FAQ area of their website) suggests, for hi-cap mags, that the owner download the spring a round or two during storage -- they say they'll last longer if you do. As noted above, however, not all mag designs require that.

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Plus one!!!

FWIW, I think the OP was asking more about the firing mechanism than the magazine springs, but that was all helpful info. IMO, you will not harm anything. Ever gun I own, shotguns, rifles, pistols, is cocked right now and some of them have been stored that way for decades. The exception is tow single shot guns that are stored with the hammer down. All function fine.

Only the pistols are stored with a round in the chamber with full, or nearly full, magazines. I need them for defense they need to be loaded. I also keep a couple of AR magazine loaded. I doubt I will ever need that (I HOPE I never need any of it) but its there just in case.

Thanks that was a good question

I want to follow up on my thank you. Sometimes those of us that are new to the forums hesitate to ask a question but are appreciative of those that jump in and ask it. Secondly there are no answers that go too far because we sometimes get the answer to the follow up question before we even ask it. So I say thanks again for the information. I got an answer to a question I had not even asked myself and an answer to something that has been rolling around in my mind.

Thank you all so much for the info. Very informative and answered my question.

The stuff cited above had to do with recoil springs and magazine springs, but springs are springs, and they can all be worn out the same way. And compressing (or in the case of a flat spring, bending) them too far is generally what does it. (That excerpt from another forum was really focused on coil springs, but even flat springs respond basically in the same way.)

When gun designers are concerned about long spring life, they'll build the springs so that when used they won't be compressed too far. If the designer needs to fit a spring into a smaller area/or be compressed more completely (as with a high capacity magazine or the recoil spring in a very small gun), but still do much the same work, they'll let the spring get compressed more than normal, and it will wear out a bit more quickly.

Push any material past it's "elastic limit" -- be it glass, rubber, plexiglass, wood, plastic, steel or aluminum -- it will be begin to degrade and eventually will fail or even break. Don't compress it too far, and it can continue to function for a very long time.

With most coil springs in guns, you generally get hints that a spring is getting weak long before it actually breaks -- failures to feed properly, light strikes, etc.

The springs in most hammer or striker mechanisms are designed to have long lives, and they don't have to make them extra small. You can leave hammer or striker springs charged or compressed without much concern. Using the safety won't prolong spring life, but it might help prevent a negligent discharge.